Bimetal MOFs-mediated morphology-controllable catalyst, and preparation method and application thereof

Abstract

The invention discloses a bimetallic MOFs mediated morphology-controllable catalyst, a preparation method and application thereof, and the preparation method comprises the following steps: respectively adding an iron salt, a cobalt salt and an organic ligand into an organic solvent, and then adding an alkaline regulator and a surfactant; transferring the stirred solution into a reaction kettle to carry out solvothermal reaction, and centrifuging, washing and drying the suspension after the reaction to obtain a bimetal organic framework (MOFs) precursor; and carrying out heat treatment in a gas atmosphere to obtain the catalyst. The bimetallic MOFs are obtained through a one-step solvothermal method, the size and morphology of the product are regulated through the alkaline regulator, agglomeration of catalyst nanoparticles can be reduced by adding the surfactant, the preparation method is simple, the specific surface area of the product is high, and when the catalyst is used for preparing high-carbon hydrocarbon through catalytic hydrogenation of carbon dioxide, the yield of the product is high. The conversion rate of carbon dioxide reaches up to 47.82%, the selectivity of high-carbon hydrocarbon reaches 59.68%, the selectivity of by-products carbon monoxide and methane is low, and the catalytic activity is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and in particular relates to a bimetallic MOFs-mediated morphology-controllable catalyst, a preparation method and an application thereof. Background Art

[0002] The combustion of fossil fuels leads to a large amount of carbon dioxide emissions, which brings a series of environmental problems. In order to solve this problem, people are looking for various methods to capture and utilize carbon dioxide. The hydrogenation of carbon dioxide is not only conducive to alleviating the environmental problems caused by excessive carbon dioxide emissions, but also can produce high value-added hydrocarbon chemicals. Among them, the improved Fischer-Tropsch (FT) reaction is an effective way. Carbon dioxide and hydrogen generate the intermediate CO through the RWGS reaction (the active phase is Fe3O4), and then CO reacts with H2 through the FT reaction (the active phase is Fe5C2) to generate hydrocarbons. However, the catalyst in this reaction has problems such as easy deactivation, difficult to control, and low activity. The reason is that the specific surface area of ​​the catalyst is small. Therefore, it is essential to study the size and morphology of the catalyst in the carbon dioxide hydrogenation reaction. A large number of studies have shown that metal organic frameworks (MOFs) are a kind of material with a unique structure and high specific surface area formed by metal ions and organic ligands. Under appropriate conditions, the porous structure and morphology of MOFs crystals are retained during the conversion process, and porous metal oxides and porous metal oxide / carbon composite catalysts with rich structures and excellent performance can be obtained. Therefore, regulating the size and morphology of the catalyst is an important way to improve the activity of the catalyst.

[0003] CN115445669A provides a carbon dioxide hydrogenation catalyst prepared by mixing metal and acid-treated molecular sieve, but the carbon dioxide conversion rate of the catalyst in the reaction is low (20%). Patent CN114870886A provides a multifunctional catalyst (Na-Fe3O4 / ZSM-5) composited with metal oxide and molecular sieve. The catalyst has a high selectivity for high carbon hydrocarbons (68.5%) and a low selectivity for methane (2.1%), but a low carbon dioxide conversion rate (22.4%). Patent CN116899570A discloses a metal catalyst and its preparation method and application. The preparation method of the patent is to pyrolyze the precursor in a hydrogen atmosphere or a nitrogen atmosphere to obtain the metal catalyst, which also has high hydrogenation activity for benzene, and the conversion rate of benzene reaches more than 80% at 180°C. The catalysts prepared by the above methods have low conversion rates for carbon dioxide, and the preparation process is complicated, the catalyst is easy to agglomerate, and the stability is poor.

[0004] Therefore, it is very important to develop a catalyst for the catalytic hydrogenation of carbon dioxide to produce higher carbon hydrocarbons with simple preparation method, low energy consumption and high activity. Summary of the invention

[0005] In view of the shortcomings of the prior art described above, the purpose of the present application is to provide a preparation and application of a bimetallic MOFs-mediated morphology-controllable catalyst to solve the problems of the existing catalysts, such as the complicated preparation process and the inability to balance the carbon dioxide conversion rate and the high carbon hydrocarbon selectivity.

[0006] To solve the above problems, the technical solution adopted in this application is:

[0007] The preparation and application of a bimetallic MOFs-mediated morphology-controllable catalyst described in the present invention is characterized by comprising the following steps:

[0008] Step 1, respectively adding a transition metal compound and an organic ligand to an organic solvent, mixing the two solutions after they are completely dissolved, adding an alkaline regulator and a surfactant and stirring to obtain a reaction solution; the transition metal compound is a mixture of a first transition metal soluble salt and a second transition metal soluble salt;

[0009] Step 2, transferring the reaction solution to a reactor for solvothermal reaction to obtain a suspension;

[0010] Step 3, centrifuging, washing and drying the suspension obtained in step 2) to obtain a bimetallic organic framework precursor;

[0011] Step 4: heat-treating the bimetallic organic framework precursor obtained in step 3) under a gas atmosphere to obtain a bimetallic organic framework-mediated catalyst.

[0012] As a preference of the present application, the first transition metal soluble salt is selected from at least one of iron salts and hydrates of iron salts.

[0013] As a preference of the present application, the iron salt is selected from at least one of ferric nitrate, ferric chloride and ferric sulfate.

[0014] As a preference of the present application, the second transition metal soluble salt is selected from at least one of cobalt salts, manganese salts, copper salts, hydrates of cobalt salts, hydrates of manganese salts, and hydrates of copper salts.

[0015] As a preference of the present application, the second transition metal is selected from at least one of a cobalt salt and a hydrate of a cobalt salt.

[0016] As a preference of the present application, the cobalt salt includes at least one of cobalt nitrate, cobalt acetate and cobalt sulfate.

[0017] As a preference of the present application, the organic ligand is selected from at least one of terephthalic acid and trimesic acid.

[0018] As a preference of the present application, the molar ratio of the first transition metal soluble salt to the second transition metal soluble salt is (0.01-3):(1-2).

[0019] As a preferred embodiment of the present application, the organic solvent is at least one of N,N-dimethylformamide (DMF), methanol and ethanol, preferably N,N-dimethylformamide (DMF).

[0020] As a preference of the present application, the ratio of the total amount of the transition metal compound, the amount of the organic ligand, the amount of the regulator, and the amount of the surfactant is 1:(0.5-1):(0.01-1):(0.001-0.01).

[0021] As a preferred embodiment of the present application, the alkaline regulator is at least one of sodium hydroxide, potassium hydroxide, triethylamine and polyvinylpyrrolidone, preferably sodium hydroxide.

[0022] As a preferred embodiment of the present application, the surfactant includes at least one of ethylene glycol, glycerol, and cetyltrimethylammonium bromide, preferably cetyltrimethylammonium bromide (CTAB).

[0023] As a preference of the present application, in step 2, the hydrothermal reaction temperature is 110° C., and the hydrothermal time is 12 to 36 hours.

[0024] As a preferred embodiment of the present application, in step 3, the washing liquids used for washing are N,N-dimethylformamide (DMF), ethanol solution and deionized water in sequence.

[0025] As a preferred embodiment of the present application, the bimetallic organic framework precursor is heat treated in a gas atmosphere, and the heat treatment atmosphere includes at least one of nitrogen, argon, air, hydrogen, carbon monoxide or a mixed gas, preferably a mixed gas (argon first and then air).

[0026] The present invention also provides a bimetallic MOFs-mediated catalyst prepared according to the preparation method.

[0027] The present invention also provides an application of the bimetallic MOFs-mediated catalyst in the preparation of high-carbon hydrocarbon compounds by carbon dioxide hydrogenation reaction.

[0028] As a preferred embodiment of the present application, the application is carried out according to the following steps:

[0029] loading the catalyst into a fixed bed reactor;

[0030] Before the mixed gas reaction, the catalyst needs to be reduced and activated in a hydrogen atmosphere. The reduction temperature is 300-500°C and needs to be carried out under normal pressure. After the reduction is completed, the temperature is lowered to below 100°C and the mixed gas is switched to carry out catalytic reaction to obtain high-carbon hydrocarbon compounds; the catalytic reaction temperature is 250-400°C, the reaction pressure is 1-5MPa, and the reaction volume space velocity is 1500-6000h -1 The mixed gas is a mixture of three gases: H2, CO2 and N2. The volume fraction of H2 in the mixed gas is 65-75%, the volume fraction of CO2 is 20-25%, the volume fraction of N2 is 5-10%, and the sum of the volume fractions of each component is equal to 100%.

[0031] As a preference of the present application, the high-carbon hydrocarbon compound is a hydrocarbon substance with a carbon number ≥5.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The preparation method of the present invention is simple, and an efficient one-step solvent thermal synthesis method is used to synthesize the catalyst;

[0034] (2) Compared with a single iron-based metal organic framework, the present invention optimizes the component content of the catalyst by adjusting the iron-cobalt molar ratio, and the synergistic effect between the two metals can enable the carbon dioxide hydrogenation reaction to have a higher conversion rate and high carbon hydrocarbon selectivity;

[0035] (3) The present invention provides a bimetallic MOFs-mediated morphology-controllable catalyst preparation and application, in which an alkaline regulator is added during the preparation process to control the size and morphology of the product. The deprotonation of the alkaline regulator can quickly generate many small seed crystals to accelerate the nucleation process, thereby obtaining a smaller product;

[0036] (4) Adding surfactants during the preparation process can prevent the rapid growth of crystals, make the crystal nuclei evenly dispersed, and effectively reduce the agglomeration between catalysts, thereby obtaining monodispersed and more uniformly sized micro-nano MOFs, increasing the specific surface area of ​​the catalyst and the dispersion between active components, and ultimately improving the performance of the catalyst.

[0037] (5) The preparation and application of an iron-cobalt bimetallic MOFs-mediated catalyst provided by the present invention uses a unique MOFs structure as a precursor, and pyrolysis under appropriate conditions can obtain a catalyst with rich structure and excellent performance. The traditional heat treatment of MOFs is usually direct pyrolysis in an inert atmosphere or air atmosphere. The heat treatment of MOFs used in the present invention is multi-step pyrolysis (first pyrolysis under an inert gas to obtain carbon-coated highly dispersed metal or metal oxide particles, and then calcination in an air atmosphere to obtain metal oxides with high crystallinity). BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 are the XRD patterns of catalysts mediated by FeCo-MOFs with different ratios under nitrogen atmosphere.

[0039] Figure 2 It is the SEM image of bimetallic MOFs prepared by adding alkaline regulator and surfactant. DETAILED DESCRIPTION

[0040] The following describes the implementation of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application.

[0041] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0042] In addition, it should be understood that one or more method steps mentioned in this application do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in this application does not exclude the existence of other devices / apparatuses before or after the combination device / apparatus or the insertion of other devices / apparatuses between these two explicitly mentioned devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or the scope of implementation of this application. Changes or adjustments in their relative relationships shall also be regarded as the scope of implementation of this application without substantial changes in the technical content.

[0043] The present application is further described below in conjunction with specific embodiments, but the protection scope of the present application is not limited thereto.

[0044] Example 1

[0045] Step 1, dissolving 0.025 mol of ferric chloride hexahydrate (FeCl3·6H2O) and 0.025 mol of cobalt nitrate hexahydrate (Co(NO3)2·6H2O) in 60 mL of DMF, dissolving 0.025 mol of terephthalic acid in 60 mL of DMF, mixing and stirring the two solutions for 10 min after complete dissolution, adding 5 ml of sodium hydroxide solution (the molar concentration is 4 mol / L) dropwise to the mixed solution and stirring for 10 min, and finally adding 0.001 mol of hexadecyltrimethylammonium bromide (CTAB) to the solution to obtain a reaction solution;

[0046] Step 2, the reaction solution was transferred to a reactor and reacted at 110°C for 36 hours, the obtained suspension was centrifuged (rotation speed was 6000rmp, centrifugation was 5min), washed, and dried to obtain a bimetallic organic framework precursor; during washing, it was washed three times with DMF, anhydrous ethanol, and deionized water in sequence, and the washed product was placed in a 70°C oven and dried for 12 hours to finally obtain a bimetallic organic framework precursor Fe1Co1-MOF;

[0047] Step 3: Place the bimetallic organic framework precursor in a tubular furnace, introduce inert gas N2, heat to 500°C at a heating rate of 5°C / min and pyrolyze for 3 h to obtain a bimetallic MOFs-mediated Fe1Co1@C catalyst.

[0048] Example 2

[0049] The preparation methods of this embodiment are basically the same as those of Embodiment 1, except that the molar ratio of the first transition metal soluble salt to the second transition metal soluble salt is different. In this embodiment, the molar ratio of the first transition metal soluble salt to the second transition metal soluble salt is 3:2, that is, the amount of ferric chloride hexahydrate is changed from 0.025 mol to 0.03 mol, and the amount of cobalt nitrate hexahydrate is changed from 0.025 mol to 0.02 mol, and the rest of the processes are exactly the same.

[0050] The product obtained in this embodiment is a bimetallic organic framework Fe3Co2-MOF, that is, a Fe3Co2@C catalyst mediated by bimetallic MOFs.

[0051] Example 3

[0052] The preparation methods of this embodiment are basically the same as those of Embodiment 1, except that the molar ratio of the first transition metal soluble salt to the second transition metal soluble salt is different. In this embodiment, the molar ratio of the first transition metal soluble salt to the second transition metal soluble salt is 2:1, that is, the amount of ferric chloride hexahydrate is changed from 0.025 mol to 0.007 mol, and the amount of cobalt nitrate hexahydrate is changed from 0.025 mol to 0.003 mol, and the rest of the processes are exactly the same.

[0053] The product obtained in this embodiment is a bimetallic organic framework Fe2Co1-MOF, that is, a Fe2Co1@C catalyst mediated by bimetallic MOFs.

[0054] Example 4

[0055] The preparation method of this comparative example is basically the same as that of Example 2, except that the ratio of the total amount of the transition metal compound, the amount of the organic ligand, the amount of the alkaline regulator, and the amount of the surfactant is different. In this example, the ratio of the total amount of the transition metal compound, the amount of the organic ligand, the amount of the alkaline regulator, and the amount of the surfactant is 1:0.5:0.01:0.001, and the rest of the processes are exactly the same.

[0056] Example 5

[0057] The preparation method of this comparative example is basically the same as that of Example 2, except that the ratio of the total amount of the transition metal compound, the amount of the organic ligand, the amount of the alkaline regulator, and the amount of the surfactant is different. In this example, the ratio of the total amount of the transition metal compound, the amount of the organic ligand, the amount of the alkaline regulator, and the amount of the surfactant is 1:1:0.03:0.005, and the rest of the processes are exactly the same.

[0058] Example 6

[0059] The preparation methods of this embodiment are basically the same as those of embodiment 2, except that the inert gas in step 4 is different. The inert gas in this embodiment is argon, and the rest of the processes are exactly the same.

[0060] The product obtained in this example is a Fe3Co2@C(Ar) catalyst mediated by bimetallic MOFs.

[0061] Example 7

[0062] The preparation methods of this embodiment are basically the same as those of Embodiment 2, except that the method of heat treating the bimetallic organic framework precursor under a gas atmosphere is different. In this embodiment, the bimetallic organic framework precursor is calcined in air, heated to 500°C at a heating rate of 5°C / min and calcined for 3 hours, and the rest of the processes are exactly the same.

[0063] The product obtained in this example is a Fe3Co2-KQ catalyst mediated by bimetallic MOFs.

[0064] Example 8

[0065] The preparation methods of this embodiment are basically the same as those of Example 2, except that the heat treatment method of the bimetallic organic framework precursor under the gas atmosphere is different. This embodiment uses a multi-step pyrolysis method to heat treat the bimetallic organic framework Fe3Co2-MOF prepared in step 3, and the rest of the processes are exactly the same.

[0066] The multi-step pyrolysis method in this embodiment is specifically operated as follows:

[0067] First, the bimetallic organic framework precursor Fe3Co2-MOF was placed in a tube furnace and argon gas was introduced for pyrolysis at a temperature of 500°C and a pyrolysis time of 3 h to obtain a pyrolysis product.

[0068] The pyrolysis product was then calcined in air, heated to 500°C at a heating rate of 5°C / min and calcined for 3 h to obtain a bimetallic MOFs-mediated Fe3Co2-Ar-KQ catalyst.

[0069] Comparative Example 1

[0070] The preparation method of this comparative example is basically the same as that of Example 1, except that ferric chloride hexahydrate is used to replace the transition metal compound in Example 1, and the rest of the processes are exactly the same.

[0071] The product obtained in this comparative example is a metal organic framework Fe-MOF, and a MOFs-mediated Fe@C catalyst is obtained.

[0072] Comparative Example 2

[0073] The preparation method of this comparative example is basically the same as that of Example 1, except that cobalt nitrate hexahydrate is used to replace the transition metal compound in Example 1, and the rest of the processes are exactly the same.

[0074] The product obtained in this comparative example is a metal organic framework Co-MOF, and a MOFs-mediated Co@C catalyst is obtained.

[0075] Comparative Example 3

[0076] The preparation method of this comparative example is basically the same as that of Example 1, except that the regulator in step 1 is changed from 5 ml of sodium hydroxide solution with a molar concentration of 4 mol / L to 5 ml of acetic acid with a molar concentration of 4 mol / L, and the product obtained in this comparative example is a bimetallic MOFs-mediated Fe3Co2@C catalyst (acetic acid).

[0077] Comparative Example 4

[0078] The preparation method of this comparative example is basically the same as that of Example 1, except that the alkaline regulator and surfactant in step 1 are not added, and the rest of the processes are exactly the same.

[0079] Phase Characterization

[0080] The crystal structure and phase composition of the catalyst were characterized by using an ARL SCINTAG X′TRA X-ray diffractometer produced by Thermo Fischer Company of the United States, with Cu Kα rays (wavelength of 0.154056nm) as the X-ray source. The tube voltage was 40kV, the tube current was 40mA, the scanning step was 0.02, and the scanning range was 20-70°. The X-ray diffractometer was used to analyze the phase composition of the catalyst.

[0081] Morphological characterization:

[0082] SEM characterization was performed using a Zeiss G500 scanning electron microscope at an accelerating voltage of 5kV to observe the surface morphology of the sample at different magnifications. The sample was prepared as thin as possible. Due to the poor conductivity of the sample, it was necessary to perform a 120s gold spray treatment before shooting to better assist electron microscopy imaging. The specific reagent preparation and test steps were carried out according to the instructions.

[0083] The performance of the catalysts prepared in Examples 1 to 8 and Comparative Examples 1 to 4 was evaluated by the following method:

[0084] The catalyst performance test was carried out in a fixed bed reactor. 0.5 mL of catalyst with a size of 60-100 mesh and 5.5 mL of quartz sand with the same mesh size were measured, mixed evenly and loaded into the isothermal zone of the fixed bed reactor. The catalytic reaction conditions were a temperature of 300 ° C, a reaction pressure of 1 MPa, and a reaction volume space velocity of 3000 h -1 The volume fraction ratio of the mixed reaction gas H2 / CO2 / N2 is 69% / 23% / 8%, where N2 is the internal standard gas for gas chromatography analysis. The carbon dioxide, carbon monoxide, and methane in the gas phase products are quantitatively analyzed by an online gas chromatograph equipped with a TCD detector, and the hydrocarbon compounds in the gas products are quantitatively analyzed by an online gas chromatograph equipped with a FID detector. Finally, the carbon dioxide conversion rate and the selectivity of each product are calculated. The test results of carbon dioxide hydrogenation performance are listed in the table.

[0085] Table 1 Performance test of different catalysts

[0086]

[0087] In Comparative Examples 1-2, a single metal organic framework containing only Fe or Co prepared by a solvothermal method was pyrolyzed under an inert atmosphere and then combined with Figure 1From the XRD diagram in, the single metal Fe or Co respectively presents the diffraction peak of Fe2O3 or Co3O4, and has a high crystallinity, but the catalytic performance of the single metal component is low. In order to improve the catalytic performance of the single metal Fe or Co catalyst, a bimetallic MOFs-mediated bimetallic catalyst with different iron-cobalt ratios was prepared by solvent thermal synthesis. In Examples 1-3, the component content of the MOFs-mediated catalyst was changed by adjusting the iron-cobalt ratio. After the iron-cobalt bimetallic MOFs were pyrolyzed by N2, the diffraction peak of CoFe2O4 appeared, indicating that the metal Fe and Co interacted strongly and an iron-cobalt alloy was generated. It can be seen from the evaluation results that the catalytic performance is best when the iron-cobalt ratio is 3:2. The bimetallic MOFs with a high specific surface area and a spindle-shaped structure of a regular dodecahedron will maintain their original porosity and morphology after heat treatment. Comparing Examples 1-3 and Comparative Examples 3-4, whether to add a regulator will directly affect the coordination ability of the metal and the ligand during the formation of the bimetallic MOFs. The morphology of the catalyst can be regulated by adding a regulator and a surfactant. The NaOH added in Examples 1-8 accelerates the nucleation process of the crystal nucleus through protonation to obtain a product with a relatively small size. In addition, the addition of a surfactant can prevent the rapid generation of the crystal nucleus, make the crystal nucleus evenly dispersed, and effectively reduce the agglomeration between the catalysts, thereby obtaining monodisperse and more uniformly sized micro-nano MOFs, increasing the specific surface area of ​​the catalyst and the dispersion between the active components, and ultimately improving the performance of the catalyst.

[0088] In Examples 6-8, the atmosphere and method of heat treatment of bimetallic MOFs are different. The traditional heat treatment of metal organic frameworks is direct pyrolysis in an inert atmosphere or air atmosphere. The present invention adopts a multi-step pyrolysis method for bimetallic MOFs (first pyrolysis under an inert gas to obtain carbon-coated highly dispersed metal or metal oxide particles, and then calcination in an air atmosphere to obtain metal oxides with higher crystallinity).

[0089] Therefore, in the process of preparing the catalyst, the ratio of the iron-cobalt bimetallic components was adjusted to form an iron-cobalt alloy or a bimetallic oxide, the morphology and size of the catalyst were adjusted by adding an alkaline regulator and a surfactant, and the bimetallic organic framework precursor was obtained and then subjected to multi-step pyrolysis, thereby improving the conversion rate of carbon dioxide and the selectivity of high-carbon hydrocarbons, which were 47.82% and 59.68%, respectively.

[0090] The above examples are for the purpose of illustrating the embodiments disclosed in the present application and should not be construed as limiting the present application. In addition, the various modifications listed herein and the variations of methods and compositions in the invention are obvious to those skilled in the art without departing from the scope and spirit of the present application. Although the present application has been specifically described in conjunction with various specific preferred embodiments of the present application, it should be understood that the present application should not be limited to these specific embodiments. In fact, various modifications obvious to those skilled in the art as described above to obtain inventions should be included within the scope of the present application.

Claims

1. Preparation and application of bimetallic MOFs-mediated morphology-controllable catalysts, characterized in that: The following steps are involved: Step 1, respectively adding a transition metal compound and an organic ligand to an organic solvent, mixing the two solutions after they are completely dissolved, adding an alkaline regulator and a surfactant, and stirring to obtain a reaction solution; the transition metal compound is a mixture of a first transition metal soluble salt and a second transition metal soluble salt; Step 2, transferring the reaction solution to a reactor for reaction, and the obtained suspension is centrifuged, washed multiple times, and dried to obtain a bimetallic organic framework precursor; Step 3: heat-treating the bimetallic organic framework precursor obtained in step 2 under a gas atmosphere to obtain a bimetallic MOFs-mediated catalyst.

2. The method for preparing a bimetallic MOFs-mediated morphology-controllable catalyst according to claim 1, characterized in that: The first transition metal soluble salt is selected from at least one of iron salts and hydrates of iron salts; the second transition metal soluble salt is selected from at least one of cobalt salts, manganese salts, copper salts, hydrates of cobalt salts, hydrates of manganese salts and hydrates of copper salts; The organic ligand is selected from at least one of terephthalic acid and trimesic acid.

3. The preparation and application of the bimetallic MOFs-mediated morphology-controllable catalyst according to claim 1, characterized in that: The ratio of the total amount of the transition metal compound, the amount of the organic ligand, the amount of the regulator, and the amount of the surfactant is 1:(0.5-1):(0.01-1):(0.001-0.01).

4. The molar ratio of the first transition metal soluble salt to the second transition metal soluble salt is (0.01-3):(1-2).

5. The preparation and application of bimetallic MOFs-mediated morphology-controllable catalyst according to claim 1, characterized in that: The alkaline regulator includes at least one of sodium hydroxide, potassium hydroxide, triethylamine and polyvinylpyrrolidone; the surfactant includes at least one of ethylene glycol, glycerol and hexadecyltrimethylammonium bromide.

6. The preparation and application of bimetallic MOFs-mediated morphology-controllable catalyst according to claim 1, characterized in that: The bimetallic organic framework precursor is heat-treated in a gas atmosphere, wherein the heat-treatment atmosphere includes at least one of nitrogen, argon, air, hydrogen, carbon monoxide or a mixed gas.

7. A bimetallic MOFs-mediated morphology-controllable catalyst obtained according to the preparation method according to any one of claims 1 to 6.

8. Use of the bimetallic MOFs-mediated morphology-controllable catalyst as claimed in claim 7 in the preparation of high-carbon hydrocarbon compounds by catalytic hydrogenation of carbon dioxide.

9. The use according to claim 8, characterized in that: The application is carried out in the following steps: Before the mixed gas reaction, the catalyst needs to be reduced and activated in a hydrogen atmosphere. The reduction temperature is 300-500°C and needs to be carried out under normal pressure. After the reduction is completed, the temperature is lowered to below 100°C and then switched to the mixed gas for catalytic reaction to obtain high-carbon hydrocarbon compounds; the catalytic reaction temperature is 250-400°C, the reaction pressure is 1-5MPa, and the reaction volume space velocity is 1500-6000h -1 The mixed gas is a mixture of three gases: H2, CO2 and N2. The volume fraction of H2 in the mixed gas is 65-75%, the volume fraction of CO2 is 20-25%, the volume fraction of N2 is 5-10%, and the sum of the volume fractions of each component is equal to 100%.

10. The use according to claim 8, characterized in that: The high-carbon hydrocarbon compound is a hydrocarbon substance with a carbon number of ≥5.

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